package com.hmdp.service.impl;

import com.hmdp.service.ILock;


import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;


import java.util.Collections;
import java.util.UUID;
import java.util.concurrent.TimeUnit;


public class SimpleRedisLock implements ILock {
    public static final String KEY_PREFIX = "lock:";

    public static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    private  String name;
    private final StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name,StringRedisTemplate stringRedisTemplate){
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    public static final String ID_PREFIX = UUID.randomUUID().toString() + "-";

    @Override
    public boolean tryLock(long timeoutSec) {
    String threadId = ID_PREFIX + Thread.currentThread().getId();
    Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name,threadId + "",timeoutSec, TimeUnit.SECONDS);
    return Boolean.TRUE.equals(success);
    }


    @Override
    public void unlock() {
    //lua脚本解决原子性问题版
        stringRedisTemplate.execute(UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId());

    }

//    @Override
//    public void unlock() {
//        //现在拿到线程的
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//        //一开始向线程存的
//        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//        //一样就删
//        if(threadId.equals(id)){
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//    }
}
